A Porous Coordination‐Polymer Crystal Containing One‐Dimensional Water Chains Exhibits Guest‐Induced Lattice Distortion and a Dielectric Anomaly

Ice one: A porous molecular crystal with guest water molecules in the channels—La2Cu3NH (CH2COO) 26 (H2O) n (see picture) —exhibits a distinct peak for the dielectric constant at 180 K (εr≈150) with the electric field parallel to the channel direction. This crystalline compound also shows a large enhancement of εr above 250 K and a characteristic antiferroelectric hysteresis coupled with a liquid–solid transition of the guest water molecules at around 350 K.